All the other planets have interesting hooks to them. Hearthside is tidally locked, Sweetwater is an ocean world. Yih has a ring and is the cradle of life at Focus, Welkinstead has cloud cities, and Moonlitter is nearly uninhabitable itself but has a bunch of moons.

But Newhome doesn't have anything other than being the first terraformed planet. Perhaps Newhome's hook is that nearly the entire population lives in a single giant archology that's also a speace elevator. Here's how I see this panning out.

Because Newhome was first, it's also the worst. The tech used to maintain its biosphere is both ancient and hard to replace. Some time in the past, the thought of that infrastructure breaking down caused a demographic crisis as people fled what they thought was an iminant disaster and those that stayed often chose not to have a litter. But much like the population bomb that mid-20th century humans were sure was coming, the collapse never happened, and centuries of low fertility left a permanent mark on Newhome culture. Even in the midst of prosperity, new litters are a rare sight.

Population densities across the planet plummeted, and those that remained gathered in the largest city. This city evolved into a single giant archology built around an existing space elevator. The building is unfathomably massive, stretching miles into the sky and rooted miles under the earth. Because the building was not constructed all at once, it's a hodgepodge of different architectural styles and tech levels mashed together. Some sections are so dense people are packed paw on tail, while other areas are almost or completely abandoned. People, on four legs or two, who love exploring massive indoor areas love poking around the less-traveled sections. The building is so huge that different parts have their own microclimates.

In fact, the building may not be one building but two, with the other located at the antipodes with a tunnel connecting them running through the core of the planet.